1. Field of the Invention
This invention is generally directed to cattle or livestock guards or gates of the type which are designed to permit vehicular traffic to pass thereover when traveling into or out of an enclosed area while simultaneously prohibiting livestock from passing therethrough. More particularly, however, the invention is directed to an electrical livestock guard which includes a selectively electrified wire mesh or steel wire rope grid which is retained in a taut generally horizontal orientation in vertically spaced relationship to a metallic base by springs or other resilient connections which mount the grid to insulators mounted to the base. In this manner, the grid is elevated to prohibit livestock passing with respect thereto but is vertically yieldable so as to allow vehicles to pass there over. Also, the base of the electrical livestock guard or gate includes a plurality of end and intermediate segments which can be selectively joined in generally coextensive relationship with respect to one another thereby allowing the base to be adjusted in length to suit varying widths of passageways or openings through a fence.
2. History of the Related Art
The use of cattle or livestock guards in farm or ranch areas to replace gates and fences at locations where vehicular access is necessary is well known. Such guards are specifically designed to do away with the inconvenience of having to physically open and close gates and also prevent livestock from escaping from a fenced enclosure in those instances where, through accident or inadvertance, a gate is not properly or adequately closed and/or locked. Some of the original cattle guards were created due to the necessity for railroads to extend through grazing ranges and yet restrict the movement of cattle within such areas.
Early cattle guards were specifically constructed to prevent hooved animals from being able to obtain sure footing by using spaced and elevated rails or poles which had generally tapered or circular cross sections. The problem associated with such structures however, is that they required a large number of heavy duty and hard to manipulate and assemble components. Such guards could not be effectively preformed in one location for later installation in another location. Also, once installed, such large and complex structures could not be easily altered in the event an increased width of access became necessary through a fence.
In an effort to overcome the disadvantages of permanently installed type cattle guards, an effort was made to provide guards which could be more portable in nature. In U.S. Pat. No. 2,800,304 to Van Alsburg, a portable cattle guard is disclosed which includes a metallic frame from which a plurality of bars are horizontally extended so as to be in space relationship to the base or frame. The rods extending across the guard are resiliently urged so that the bars could be collapsed vertically with respect to the base in order to permit vehicular traffic to pass through the opening in which the guard was installed. Unfortunately, such portable cattle guards require a large number of components which may easily become damaged due to the passage of vehicles over the structure during use. Once a particular element of the cattle guard is damaged, it is necessary to replace the element in order to maintain the effectiveness of the cattle guard. Even with these drawbacks, the overall weight of such portable guards requires a great deal of physical effort to be exerted to install the units in a given area. Further, such portable guards are not conducive to being adjusted for varying widths of passageways or openings in fenced areas and therefore specific frames must be constructed for each location.
In order to increase the effectiveness of the cattle guards such as disclosed in the patent to Van Alsburg, cattle guards were provided with metallic conductors so that electricity could be supplied to the conductors which were often in the form of elongated rods. Such conductors could thereafter be electrically connected to the conductors associated with an electrified fence. An example of this type of cattle guard is disclosed in U.S. Pat. No. 2,899,174 to Wells. However, such structures are bulky and cumbersome and not adjustable to openings or passageways through fenced areas. Further, the elements utilized for conducting electricity which form the basis of the cattle guards could easily be damaged by the passage of vehicular traffic and therefore would require frequent replacement to maintain the efficiency of the guards.
Another type of electric livestock guard or gate is disclosed in U.S. Pat. No. 2,769,617 to Hutchinson. In this structure, the rigid metallic conducting bars associated with other livestock guards were replaced by chain elements which could be retained taut by the use of springs connected to a frame to which the chain elements were mounted. With this structure, damage to the conductors associated with the livestock guard was reduced. Unfortunately, the frames were not conducive to being adjusted in size so as to permit the guards to be utilized with various openings in fenced areas. In addition, each of the chain elements would have to be individually mounted with respect to the frames thereby necessitating an increased cost for the overall livestock guard and also requiring increased maintenance to insure that each of the conductor elements was properly mounted and remained effective. The failure of one or more such flexible conductors could result in livestock being able to cross the guard without receiving an electrical impulse as is necessary to discourage their passage.
A similar type of electric cattle guard is disclosed in U.S. Pat. No. 2,512,740 to Evans. In this structure, either a single or multiple electrical conductors are provided between vertically embedded posts with the conductors resiliently urged relative to the posts to maintain tension on the conductors. Unfortunately, with this type of structure, it is necessary that the supports be embedded in the ground thus requiring an increase in manual labor to install the cattle guard in a given crossing.